Clock movement



Jan. 25, 1927.

1,615,664 H. E. WARREN CLOCK MOVEMENT Filed Aug. 18, 1926 2 Sheets-Sheet 1 Inventor: Henry E. Warren,

His A'tto'hneg 1,615 664 Jan. 25, 1927. H. E. WARREN CLOCK MOVEMENT Filed Aug. 18, 1926 2 Sheets-Sheet 2 35 3.2 a/ as Fig. 7.

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Patented Jan. 25, 1927.

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Application filed a My invention relates to clock movements, and in particular to a simple, compact driving connection between the clock motor and the hands thereof whereby second, m1nute and hour hands may be mounted on the same axis and cooperate with the same dial, and whereby the slower moving hands may be readily adjusted with'respect to the driving motor for the purpose of sett1ng the clock. Another feature of my invention IS an improved signalin device to be employed when the clock is driven by an electrio motor to indicate when the power has been off and the clock needs resetting.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding of the invention, reference is made in the following description of one form of my invention represented in the accompanying drawings, in

a which Fig. 1 represents the face of the clock showing the three clock hands mounted on the same axis and the signaling device; Fig. 2 shows the arrangement of the dr v ing mechanism directly behind the clock face, the latter being removed; Fig. 3 1s a artlally exploded perspective view of the driving mechanism, including the driving motor; Fi 4 is a sectional view taken on the centra axis and shows an additional automatic clock setting feature to be explained;'Figs. 5 and 6 are sectional views taken at right angles to each other, showing the gear reduction and the friction device employed to enable the clock hands to be set by hand; and Fig. 7 shows a spring rod before it is bent into a circular shape and inserted between the relatively adjustable parts of the friction device.

The general appearance of the clock face in the embodiment of the invention hereinafter explained is shown inFig. 1; 13, 14 and 15 represent hour, minute and second hands, respectively, all mounted on the same axis and cooperating with the same dial- An opening 16 is provided in the clock face and back of this opening is a circular indicator 17 represented in dotted lines. As shown in Figs. 2 and 3,-th1s indicator has sector 19 painted red, or oth er appropriate colors. It is SecuredLto a shaft 20 which is rotatably mounted in the clock plates 21 and 22, and extends rearward above the laminated field core 23 of the self-starting synchronous driving motor 24:. Adjacent the magnetic core 23, an iron. armature 23" secured to the shaft 20. This armature 1s overbalanced with respect to the axis of rotation of the shaft, and in the position shown in Fig. 3 the heavier portion is just off the vertical axis above the shaft, while the lighter portion is out of contact with but closely adjacent the magnetic core 23 of the motor, where it is held by magnetic attraction due to the field flux of the motor when the latter is energized. This is the normal position of the indicating device which brings the white portion of the indicator 17, which is preferably the same color as the clock face, over the openinglti. When the voltage of the distribution system to through approximately 18% degrees, bringing the red portion of the, indicator signal l? over the opening 16, thereby indicating to the next observer of the clock that the power is off or has been oil and that the clock should be re:et. If the power has come on again, the motor will start up, but will notrotate the armature 23 into its original position because the armature is now held in the new position by magnetic attraction as well as by the force'of gravity. After the clock hands are reset, the shaft is turned by hand to bring it back to its nbrmal position. By positioning the armature 23 slightly'out of cont-act with'the core 23, when in its attracted position, the alternating fiux'of the motor "does not produce the chattering noise which would be occasioned if the armature made direct contact with the/core. The sh'aftQO extends to clock case, not shown.

In describing the driving connection between the motor and clock hands, it will be assumed that the terminal shaft 25 extending forward from the motor drive is geared a sector 18 painted white, and has another down .to normally rotate in a clockwise di-' rection at one R. P. M. The forward end frictionally held in the hollow part of shaft 25, so that the second hand is driven directly at the correct speed.

The minute hand 14 is secured to and driven by a hollow shaft 27 surrounding the shaft 25. The 60 to 1 gear reduction necessary between the main drive shaft and the minute hand shaft 27 is made by means of an epicyclic gear reduction comprising a gear 28 with inwardly extending teeth secured to the shaft 27 by means of a frictional connection to be explained later, and a cooperating gear 29. This last mentioned gear is secured to a plate 30 which is normally held against rotation by reason of the arm 31 which has its outer end bent rearward through an opening 32 in one of the stationary clock plates in Figs. 2 and 3. The plate 30, together with gear 29, is mounted on an eccentric 33 secured to the main drive shaft 25. It is thus seen that as the shaft 25 rotates the gear 29 and the plate 30 to which it is secured will be given 'a rotary eccentric motion while being held from actual rotation. The opening at 32 is large enough to permit this movement of the plate 30 without binding. The external diameter of gear 29 is sufficiently less than that of the internal diameter of gear 28 so that they mesh only on one side as best shown in Fig. 5, which is a full face view taken on line 5-'-5 of Fig. 6. Gear 29 has 59 teeth and gear 28 has 60 teeth. Now, as the shaft 25 rotates in a clockwise direction at one B. P. M., it will cause gear 29 to oscillate in a clockwise direction at one B. P. M. The point of contact between gears 29 and 28 will thus move around one R. P. M. in

' a clockwise direction, and because of the dif ference in the number of teeth, gear 28 will be rotated on its axis 1/60 R. P. M. in a clockwise direction. This can be understood from a consideration of Fig. 5, where it is seen that the two gears are in mesh at the top. The teeth are directly opposite each other at-the bottom, and at the right the teeth in gear 29 are advanced tooth pitch with respect to those in gear 28. Now, when the eccentric 33 moves revolution, the teeth at the righthand side will move into exact mesh, which will necessitate gear 28 rotating revolution in a clockwise direction; In thisway, the gear 28 is moved around and is advanced the distance of one tooth for each revolution of shaft 25, thereby providing the 60 to 1 gear reduction between shaft 25 and the minute hand shaft 27, all on the same axis.

The hourhand is secured to a hollow shaft34 having a bearing on shaft 27 and an ordinary back gear having a reduction gear ratio of 12 to 1 is provided between shafts 27 and 33. This back gear comprises a wheel 35 secured to shaft 27 which meshes with a gear 36. Gear 36 is integral with a gear 37 which meshes with a gear 38 secured on shaft 34. Thus we have the three concentrically arranged shafts 25, 27 and 34 secured in the driving relation necessary to move the various clock hands at the proper 7 speeds when the speed of the main drive shaft 25 is correct.

As best shown in Fig. (3, the gear 35 is pressed on shaft 27 and is provided with a shoulder on its back side onto which the spring steel or other suitable material, such as is represented in Fig. 7, is sprung into a circular shape and placed in one of the grooves. Then when the gear 28 is fitted into its place in the holder, this piece of spring tends to straighten out. As a result, it takes the general shape shown in Fig. 5 with its ends and middle pressed against the bottom of the outer groove 41 in the holder 39 and with portions intermediate the ends and themiddle pressed against the bottom of the groove in the gear 28. This serves the purpose. of locking these parts together and provides a friction coupling between them which will not slip under ordinary conditions, but which will slip when the hands are adjusted for the purpose of setting the clock.

Where the clock is to be set by hand, the back gears 36 and 37 will be secured to a shaft 43, Figs. 2 and 3, which extends through the clock plates to the back of the clock so that these gears and the clock hands secured thereto may be set without opening the clock case, not shown. This provides for setting the hour and minute hands,but not the second hand. If it ever becomes desirable to set the second hand, it can easily be done because the shaft 26 on which it is mounted is frictionally inserted in the hollow end of shaft 25.

In certain clock systems the secondary clocks are reset from a central point and in such a system the clock may be modified to the extent shown in Fig. 4. Here the arm 31 instead of being secured in a stationary clock plate is secured into a normally stationary gear wheel 44 which is connected by gear 45 to a second electric motor, not shown. When it is desired to set the clock from a remote point, this second motor is energized and the gear 29 is rotated due to the driving connection between it and the gear 45 comprising gear 44, arm 31, and late 30 to which gear 29 is secured. In thls case the to 1 gear reduction is not involved be- Periphcral grooves 40 and '1 cause gears 29 and 28 will rotate together and the clock hands will be set quickly, af-

ter which the clock setting motor is deenergized. .This in nowa interferes with the normal operation of t e apparatus, as pre viously explained. -Where the secondary clocks are set from a remote point, the indicator 17 and the manual clock setting features will not be necessary, but either may be provided as desired. Y

In accordance with the provisions of the patent statutes, I have described the principles of operation of my invention, together with the apparatus which Inow considerto represent the best embodiment thereof but I desire to have it understood that the ap* paratus shown and described is only illustrative and that thejinvention may be car ried out by other mei'uisl What I claim as new and desire to secure by Letters Patent euiieonited States, is: 1. In a clock, a driveshaftjarran ed to normally rotate-at one B. 'P.. M., a ollow minute'handshaftconcentric with said first? mentioned shaft,,a sixty to one .gear reduction between said shafts comprising a gear wheel concentrically mounted on said hour hand shaft, said wheel having sixty inward- 1y projecting teeth, a r wheel havin fifty-nine teeth in point contact with sai first-mentioned gear, an eccentric on said drive shaft upon which said fifty-nine tooth gear is mounted, and means for normally olding said eocentrically mounted gear from rotation, but allowing it to be bodily moved by said eccentric.

2. In a clock, a pair of shafts having the same axis of rotation, a gear reduction between said shafts comprism a. pair of gear wheels having difierent num rs of teeth and meshin at one point of contact, one of said wheels Icing mounted concentrically on the driven shaft, an eccentric on the driving shaft upon which the other gear is mounted, means for normally holdmg said eccentrically mounted gear from rotation during normal operation of the clock, the ar-- rangement causing the point of contact between said gears to rotate with the eccentric eds and clock-setting means for rotating the eccentrically mounted gear.

3. In a clock, a friction device in the clock driving mechanism to permit the setting of the clock comprising a pair ofconcentrically mounted parts in contact with each other,

said parts'being provided with aligned peripheral grooves 111* their adjacent abutting su1"faces,.and a rod of sprin steel or other:

suitable material constraine in a circular shape insa'id aligned grooves which, due to its tendency to straighten out, takesa position partially in one groove and partially I in the other groove, thereby forming a. trio tional driving connection between them.

'4. In a clock, a clock face, an'electric mo tor behind said face for operating the clock,

an opening in said face, a rotatably mountaft extending from a point adjacent said opening'to a point adjacent the magnetic structure of said motor, an indicator on said shaft back of the opening in said face, and an overbalanced armature member of magnetic material on said shaft adjacent said motor structure, said armature mem-- her being capable of adjustment so as to be held in the overbalanced position by magnetic attraction when the motor is energized and to move by gravity, rotating said shaft and indicator when the motor is deenergized, said indicator being arran ed to give different'indications through t e opening in the face of the clock when in the two different positions mentioned.

5. In a clock, an electric motor for 0 er- 5 85 ating said clock, means-for indicatin w en the" electrical energy supplied to sai motor" too'ateth i"-- per esg up 

